Detectives were hunting a gunman last night who shot dead a teenager in front of up to 300 people during an ice rink disco at Streatham Ice Arena in south London on Saturday night.

The 16-year-old victim, who was named last night as James Andre Smarrt-Ford, was pronounced dead in hospital shortly after the incident. Police said the youngster was shot twice.

Seven teenagers, including an 18-year-old male, have been arrested in connection with the incident, and are being held at a south London police station.

Superintendent Gary Richardson, who is leading the murder investigation, said the teenager's family was "devastated".

Detectives said the shooting took place near the entrance of the venue but James's body was found on the ice nearby.

The teenager, who had been standing among a group of people, is thought to have run there through crowds of panicking people in an attempt to flee a gunman who fired up to three shots at him.

James, who is believed to have left school recently, was given first aid at the scene of the shooting. He was later taken to St George's hospital, Tooting, where he was pronounced dead at midnight.

Police said the gunman was described by witnesses as black and wearing dark clothing.

The disco is understood to have been dark at the time of the shooting and security staff patrolled the area with torches. "We are still trying to build up a picture of how he [the gunman] came to be here," said Mr Richardson. "Did the gunman target a gang of individuals, him on his own or, indeed, was it that he was not the intended target?"

He said police were trying to ascertain whether the dead teenager had been with friends and what he had been doing earlier in the evening. "We don't know who he came here with or how long he had been here," said Mr Richardson.

"The crucial thing at the moment is that everybody who was there, even if they think they saw nothing, should come forward so that we can identify all the people who were there," he said.

He also appealed for anyone who may have witnessed the gunman running down Streatham High Road at 11pm to come forward.

On hearing the shots, the crowd of up to 300 people, mostly in their late teens and early 20s, fled out of the main entrance and on to Streatham High Road.

Operation Trident, which investigates shootings in the black community, is handling the murder inquiry. Yesterday forensic experts were examining the murder scene and officers were studying CCTV footage.

Streatham Ice Arena, which dates back to the 1930s, is popular with young people and hosts skating classes, birthday parties and schools. The disco is a regular event which takes place on Saturday evenings, and many locals regard it as a safe place for children to socialise.

Mr Richardson said: "There have been no other shootings linked to these premises that I'm aware of, or indeed any other ice rink."

Police have urged anyone with information about the shooting to contact Operation Trident on 020 8247 4554.